The present invention relates generally to scroll machines and more specifically to unique Oldham couplings for use in such scroll-type machines.
Scroll-type machines typically employ a crankshaft operative to drive one of a pair of scroll members in orbital motion with respect to a second interleaved scroll member. In order to prevent relative rotation between the scroll members, Oldham couplings have normally been employed. The Oldham couplings have taken various forms but generally incorporate two or more pairs of keys, each pair projecting in opposite directions form an annular ring member with one pair engaging slots in the orbiting scroll member and the other pair engaging either slots in the non-orbiting scroll member or a stationary body or bearing housing.
While such Oldham couplings which are operative between the respective scroll members are effective to prevent rotation between these respective scroll members, they present design and/or assembly problems in regards to positioning of the coupling between the scroll members. Alternatively, in other applications, additional support structure and/or increased shell size may be required to support the Oldham coupling radially outwardly of the scroll members.
The use of an Oldham coupling acting between the stationary body and one of the scroll members with the other scroll member being mounted to the stationary body simplifies the above design problems but such an arrangement tends to be more costly in that both scrolls must now be accurately positioned with respect to a third element. This third element must then be provided with precise locating and alignment surfaces for each of the two scroll members in order to insure that the two scroll members are accurately rotationally positioned with respect to each other.
The present invention, however, provides an Oldham coupling which is capable of directly interconnecting the two scroll members so as to effectively prevent relative rotation therebetween while avoiding the potential design problems presented by prior designs and also reducing the number of locating and positioning surfaces required. The present invention provides an Oldham coupling positioned in underlying relationship to the orbiting scroll member with first and second pairs of keys all projecting upwardly therefrom into engagement with the respective scroll members. The positioning of the keys and shape of the coupling combines to enable the two scroll members to be directly interconnected so as to both assure positive precise rotational positioning therebetween and to thereafter prevent relative rotation therebetween in an efficient manner without the need to add additional supporting structure therefor nor the need to increase the overall size of the compressor.
Additional advantages and features of the present invention will become apparent from the subsequent description and the appended claims taken in conjunction with the accompanying drawings.